Online multiplayer games and other collaboration services have become increasingly popular as network communications have improved. Users who may be geographically distant from each other may communicate with an online service to participate together in games and/or other collaboration services. Typically, users run a client program that performs local processing and communicates with the online service to coordinate joint state of the multi-user game or service. For users to initiate participation in the same online game or online service, users may meet in an online lobby or other matching system that is associated with the online game or online service. However, if a person is not already communicating with the same lobby, or already participating in the same online service, the person may not be aware that a friend or colleague is participating. The friend or colleague can manually telephone the person or send a message with an identifier to invite the person to participate in the same online game or service. To reach people outside of the online game service, a message is typically sent through an independent messaging service, such as an online portal email service or instant message service, which is generally not limited to registered users of the online game service. However, this out-of-band messaging may be time consuming to find contact information and may distract from a current game session or other service session.
Without some out-of-band communication, it may also be difficult to confirm the identity of a player in the online game service. Many players use an alias while participating in the online game service. Some players may use the same alias as other players, which can affect the reliability of rating information that is provided by game monitoring services, which track participants in online game services.